1. Field of the Invention
The invention relates generally to the production of natural gas, oil and other fluids from wells, and more particularly to systems and methods for removing sand and other solids from these fluids.
2. Related Art
Often, in the production of oil from wells, the oil is mixed with other, unwanted substances. These unwanted substances may include fluids such as gas and water, or solids such as sand. Gas and water may be mixed with the oil in underground reservoirs or other geological formations, and may flow into the well. Sand is commonly introduced into the oil as a result of production operations which are designed to fracture oil-bearing formations and thereby allow the oil to flow into the well. This technique of fracturing oil-bearing formations may be referred to as fracturing or “fracking” the well.
The well equipment which is used to produce oil from a well typically includes components that are designed to separate the unwanted substances from the oil. For instance, a sand separator is commonly provided at the surface of the well to remove the sand that may be present as a result of fracking.
Conventional sand separation systems primarily rely on gravity to separate the sand from the fluids that are produced from a well. Typically, fluid is introduced into the central portion of a large, vertically oriented chamber through a pipe that is referred to as a stinger. The fluid flows slowly upward, typically through one or more baffles, to an outlet at the top of the chamber. The chamber has a large diameter so that the linear speed of the fluid flowing through the chamber will be minimized. This allows the sand to settle out of the fluid and fall to the bottom of the chamber, where it can be accumulated and removed.
There are various problems with the use of conventional sand separators to remove sand from oil or other fluids. For example, as noted above, the chamber of the apparatus needs to be large in order to minimize the speed of the fluid so that the sand can settle out. The large size of the apparatus can make it difficult to transport and install. Additionally, because of material cost, the sheer size of apparatus makes it more expensive.
Another problem is that it is difficult to accommodate the different operating conditions and fluid characteristics that may exist in different wells. For instance, one well may have a higher flow rate than another, so the settling of the sand out of the faster-flowing fluid may be less effective. Likewise, higher viscosity or lower temperature of the fluid may reduce settling in a conventional sand separator. Addressing these problems may require that an entirely different sand separator be used.
It would therefore be desirable to provide systems and methods for separating sand and other solids from the fluids that are produced from wells.